A national epidemic of type II diabetes likely will follow the current epidemic of obesity in U.S. children, a University of North Carolina at Chapel Hill study of 688 randomly selected, apparently healthy North Carolina children suggests.
The study, conducted by researchers at the UNC-CH schools of nursing, medicine and public health, showed 7 percent of the schoolchildren already had three of the leading risk factors for heart disease and eventual type II diabetes. Those risk factors, which together are called multiple metabolic syndrome, are high insulin levels, high blood pressure and either elevated levels of fats called triglycerides or not enough of the so-called "good cholesterol," high-density lipoproteins (HDL).
"That 7 percent doesn't sound like a lot, but when you consider that these children very probably will go on to develop type II diabetes within 10 years, it's frightening," said Dr. Joanne S. Harrell, professor of nursing at UNC-CH and director of the Center for Research on Preventing and Managing Chronic Illness in Vulnerable People. "Because we studied healthy, normal kids in five different schools, we think this is a national problem that needs to be addressed on a national level."
Harrell presented the findings Monday at the American Heart Association's 73rd Scientific Sessions in New Orleans. Co-authors of the study, all at UNC-CH, were Drs. Robert G. McMurray, professor of exercise and sport science; Shrikant I. Bangdiwala, research associate professor of biostatistics; Marsha L. Davenport, associate professor of pediatrics; and John B. Buse, associate professor of medicine. Others were biostatistician Shibing Deng and project director Chyrise Bradley, research assistant professor of nursing.
Researchers evaluated in detail the group of almost 700 children, a subset of a larger group of almost 4,000 children being studied across the state through the UNC-CH-based Cardiovascular Health in Children project, because they were concerned that so many of the children were obese. Subjects ranged in age from 11 to 14.
"Obesity is closely associated with development of type II diabetes, and just recently people have noticed a significant increase in this form of diabetes among U.S. children," Harrell said. "This is not the same as juvenile onset diabetes, which is now called type I. In type I, people don't make insulin, and in type II, their bodies become resistant over time to the action of insulin, and so their bodies make too much. Eventually, even that increased insulin is not sufficient and they develop type II."
She and colleagues determined which of the children showed one or more of the risk factors and then compared that information with their weight. They also reviewed family health histories, physical activity levels, eating habits, degree of physical maturation and other factors.
"We found that the only significant predictor of which children would have the risk factors of high insulin, high blood pressure and high triglycerides or low HDL was obesity," Harrell said. "Kids who were obese were 53 times as likely to have multiple metabolic syndrome, also called insulin resistance syndrome, as children who were not obese. That's just amazing."
Depending on the risk factor, children with only one were two to six times more likely to be obese and those with two risk factors were eight to 14 times more likely to be obese, the group found.
Harrell recommends preventing children from becoming obese in the first place and helping them lose weight if they already are too heavy for their height. Increasing their physical activity and improving their diets by limiting sweets and fats and substituting grains, fruits and vegetables are critically important for overweight children.
"Our schools need to make it easier for kids to be physically active and to provide healthful foods," the scientist said. "Schools are not the whole answer, of course, but they are the logical place to start. This is a very distressing situation."
The National Institute of Nursing Research supports the continuing Cardiovascular Health in Children study.
By David Williamson
UNC-CH News Services
Note: Harrell can be reached at 919-966-4284 or via e-mail at joanne_harrell@unc.edu. During the meeting, Nov. 12-13, she can be reached through the American Heart Association's Carole Bullock at 504-670-4000 or by leaving a message at the Ramada Limited Causeway hotel, 504-835-4141. Harrell will be back at her office on Nov. 14.